Aeolian activity in arid central Asia during the past 40000 years inferred from Lake Ailike, Xinjiang

Abstract

Aeolian activity is a mirror of climate change and a vital point for understanding the Earth’s climate system in arid and semiarid regions. The processes and forcing mechanisms of aeolian activity in this region have remained debatable and inconclusive. In this study, we used accelerator mass spectrometry 14C dating, grain-size, and high-resolution X-ray fluorescence scanning data of the sediment core Ailike-2019 taken from Lake Ailike, Xinjiang, in arid central Asia, to reconstruct the variations in aeolian activity since the mid marine isotope stage (MIS) 3. The results reveal that aeolian activity in a dry climate strengthened during the mid-late MIS 3 (40–26.7 cal kyr BP) and the last glacial maximum (26.7–20 cal kyr BP), whereas the last deglaciation (20–12 cal kyr BP) was characterized by a weakening of aeolian activity with gradually increasing humidity in the Lake Ailike region. This period was followed by dustier and relatively wet conditions during the Holocene (12–0 cal kyr BP). The aeolian activity at Lake Ailike has been mainly controlled by Siberian high-pressure since the mid-MIS 3. Strong/weak aeolian activity is usually caused by frequent/infrequent cyclonic activity through cold polar air masses seasonal movement southward/northward induced by intensified/weakened Siberian high-pressure. Meanwhile, strong/weak cold polar air masses colliding with weak/strong warm tropical air masses might induce a long/short polar front duration, resulting in frequent/infrequent aeolian activity.